using Distribution.Data;
using Microsoft.EntityFrameworkCore.Infrastructure;
using Microsoft.EntityFrameworkCore.Migrations;

#nullable disable

namespace Distribution.Migrations
{
    /// <inheritdoc />
    [DbContext(typeof(AppDBContext))]
    [Migration("20261006100000_AddRegionCode")]
    public partial class AddRegionCode : Migration
    {
        /// <inheritdoc />
        protected override void Up(MigrationBuilder migrationBuilder)
        {
            migrationBuilder.AddColumn<string>(
                name: "Code",
                table: "Regions",
                type: "varchar(50)",
                maxLength: 50,
                nullable: false,
                defaultValue: "");

            // Backfill existing rows (seeded regions first) with REG-0001, REG-0002, ... before the unique index.
            migrationBuilder.Sql(@"
                UPDATE `Regions` r
                JOIN (
                    SELECT `Id`, ROW_NUMBER() OVER (
                        ORDER BY CASE WHEN `Id` LIKE '24000000-%' THEN 0 ELSE 1 END, `CreatedAt`, `Id`) AS rn
                    FROM `Regions`
                ) x ON r.`Id` = x.`Id`
                SET r.`Code` = CONCAT('REG-', LPAD(x.rn, 4, '0'));");

            migrationBuilder.CreateIndex(
                name: "IX_Regions_Code",
                table: "Regions",
                column: "Code",
                unique: true);
        }

        /// <inheritdoc />
        protected override void Down(MigrationBuilder migrationBuilder)
        {
            migrationBuilder.DropIndex(
                name: "IX_Regions_Code",
                table: "Regions");

            migrationBuilder.DropColumn(
                name: "Code",
                table: "Regions");
        }
    }
}